Hugh d



H. D. SANBORNu CONST ANT CURRENT REGULATOR. APPLICATION FILED NOV. 5. 1911.

Patented Aug. 12,1919.

' g lj 25 lnven't owz umTED STATES PATENT OFFICE.

HUGH D. SANIBORN, OF SWAMPSCOTT, MASSACHUSETTS, ABSIGNOB TO GENERAL ELECTRIC COMPANY, A CORPORATION 01' NEW YORK.

' consrm-cunnnn'r nneuna'ron.

Patented Aug. 12, 1919.

Application filed Rovember 5, 1917. Serial No. 200,408.

To all whom it may concern:

Be it known that Lillian D. SANBORN,

a citizen of the United States, residinsg at tate Swampscott, in the county of Essex, of Massachusetts, have invented .certam new and useful Improvements in Constant-Current Re lators, of which the following is a cation.

invention relates to constant current regu ating devices of the type represented by movable coil constant-current transform- ,ers,,variable series reactances somewhat resemblmg in appearance such constant current transformers, and variable reactant-es comprising relatively movable cores and coils which are more or less drawn together or separated as thefcurrent tends to change. An object of my invention is prov de such devices with means for moving the1r parts .tolow voltage (or great reactance) positions whenever they cease to supply their loads, as when electric circuits thereof are opened. By these means the devices are automatically brought to such positions when the loads are materially reduced, that when they are next started the devices and the 01r- 'cuits attached to them are protected against unduly high currents. In carrying out my invention I employ means, preferably weights, to move the movable parts of the devices to low voltage sitions whenever the loads are materia 1y reduced, and to hold the parts in these positions until the loads are resumed. The regulating devices are relieved 'of the effects of these means (as the pulls of the weights) during the normal operations of theregulating devices. Preferably electric motors energized by auxiliary windings on the regulating. devices raise the auxiliary weights when heir effects are to be dispensed with.

In the accompanying drawings and the following'description I have shown and described in some detail the best embodiment of my invention in constant-current transformers that I am now aware of. I contemplate that m invention will find its greatest use in connection with constant current transformers, but it will be understood that my invention is not limited-to the specific embodiment here illustratedand described, nor even to transformers. The single figure of the drawing illustrates-in elevation and l more. or less diagrammatically, a constant girrent transformer embodying my inven- The-constant current transformer illustrated is, by itself, substantially of a very eommni form.h Theueore 1 is of the three ge ype, t e wi in surroundin the fiddle leg thereof. The iisual windings of this particular form of transformer comprise a winding 2 (which I shall hereafter regard as the primary winding) fixed with respwt to the core and a winding 3 (hereafter regarded as the secondarywinding) movable with respect to the core and with respect to the fixed winding 2. It will be understood that my invention is not limited however to a device in which there is a fixed primary and movable secondary winding, or to a device of a plurality of windings, or a device in which but one winding-is-r'novable. The movable winding 3 is suspended .by cords or other flexible members 4, from one end of the lever 5 which is pivoted mid- Way its ends. From the other end of the lever 5 is suspended the usual counterbalancing weight 8 by means of another cord or flexible member 9. As devices are connected to or disconnected from the secondary winding, and the current in the secondary winding thereupon tends to change, the movable windin 3 moves toward or away from the fixed winding 2 and assumes such a new poa; s1t1on in each instancethat the currentdelivered by the secondary winding is of a substantially constant value (within-,the range of the apparatus) irrespective of the number of devices connected to the second-. ary winding. The movement of the movable winding is a result of the magnetic repulsion between the two windings. The construc' *the voltage on the primary winding otherwise falls below a given value, then the movable winding moves as close as possible 1 to the fixed winding, that is to its highest voltage position. To state-this more generally, whenever the transformer ceases to supply its load, the movable winding is 1 moved to its highest voltage position. Consequently when the interrupted circuit is again closed (there being a number of translating devices ready to receive current), or to state it more generally when the load is abruptly resumed, both the transformer itself and the translating devices connected thereto are subjected to unduly high currents until the movable winding can find its proper position. My invention provides means for eliminating this undesirable feature which is found not only in constant current transformers but also in other constant current regulating devices of the type to which my invention applies.v The means I have illustrated in the drawing comprises a weight 12, which here may be called the auxiliary weight, the effect of which 1s added to the effect of the weight 8 whenever the transformer ceases to supply its load in the normal fashion. The auxiliary weight 12 is normally carried by the cord or other flexible member 13, and near its center is provided with a vertical pa$age through which the cord 9 passes freely. During the normal operation of the regulating device the auxiliary weight 12 is held above the upper end of the ath of travel of the counterbalancing weight 8; hence switch 23.

with the auxiliary weight 12 in its suspended position, it has no effect on the operation of the transformer. The cord 13 is carried by the drum '14 which by means of gears 15 is coupled with the electric motor 16. This electric motor is supplied with energy by the auxiliary winding 20, in effect a secondary winding, placed on the middle leg of the core 1 adjacent the primary winding 2. The connections 21 between the winding 20 and the motor 16 includea i'esistance member 22 in shunt to which is providedthe This switch 23 is biased to a closed position by means of the spring 24; a movable part of the switch 23 is located within the range of travel of the auxiliary weight 12, this weight 12 when near the upper end of its travel and under the influence of the motor 16 engaging the movable member of the switch 23 to open this switch and hence to open the short circuit about the resistance 22. When the switch 23 is closed and normal voltage is impressed on the primary winding 2, the auxiliary winding 20 supplies suflicient energy to rotate motor 16 and raise the auxiliary weight 12. The resistance 22 is, however, of such value that when the switch 23 is open and hence thelresistance 22 effective, the motor 16 can receive substantially only suflicient energy to hold it against backward rotation under the pull of the weight 12; in other words, with the resistance 22 in circuit the motor 16 can receive from the auxiliary winding 20 substantially only sufiicient energy to lock the motor against the pull of the weight 12.

vthe proper A stop 26 attached to the core 1 limits the elevation of the auxiliary weight 12 in case the resistance 22 is of insuflicient value to altogether stop the motor. In series with the secondary circuit is a rela or switch 27 which under the influence of gravity normally tends to open its contacts 28. These contacts 28 are connected in the circuit between the motor terminals and the winding 20 as illustrated. Under the action of current in the secondary winding, the armature of the relay 27 is held in an elevated position with its contacts 28 bridged and the circuit between the motor 16 and winding 20 closed thereat. The value of the current necessary to raise the armature of the relay 27 will be understood from the following description of the operation of my invention.

The operation of this device is as follows: Before any energy is supplied to the primary winding of the regulating device, the motor 16 is without energy, the auxiliary weight 12 rests upon the weight 8 in their lowermost positions, the switch 23 is closed, the circuit between the motor 16 and the winding 20 is broken at the contacts 28, and the movable winding 3 is held in its uppermost or lowest voltage position by the combined efi'ects of the weights 8 and 12. When thereafter energy is supplied to the primary winding 2, the secondary winding 3 and the devices connected thereto have impressed upon them the minimum voltage and are subjected to the minimum current. The cur rent flowing through the secondary winding 3 and the devices connected thereto raises the armature of the relay 27 and closes the circuit at the contacts 28, and thereupon the motor 16 receives suflicient energy from the auxiliary winding 20 to rotate the drum 141 and raise the auxiliary, weight 12 fromits position in engagement with the weight 8-; the weight 12 continues its upward movement until it engages with the movable part of the switch 23 and opens that switch whereupon the motor is either locked with the weight 12 in its elevated position by reason of the insertion of the resistance 22 in series with the motor 16, or receives such diminished power as-to continue the elevation of the weight 12 only into engagement with the stop 26. As the weight 8 and hence the movable winding 3 is relieved of the effects of the weight 12, the movable Winding 3 gradually falls until it reaches position as determined by the repulsion of the windings 2 and 3. Hence instead of impressing on the secondary circuit a voltage in excess of the required voltage and subjecting the secondary winding and the devices connected thereto to undue currents (as heretofore), a minimum voltage and current is first impressed on the secondary circuit and then the voltage and current are raised to the proper values. So long as the regulating device continues thereafter to supply its load in a proper manner, it operates as though the auxiliary weight12 and the apparatus controlling the osition of this weight were absent. If,

owever, the secondary circuit is opened at any time, the armature of the relay 27 falls and the contacts 28 and the circuit to the motor 16 are opened, on the other hand.

should the primary circuit be 0 ened, the auxiliary winding 20 becomes una' le to supply energy to the motor-'16. Under either of these conditions the motor 16 is unable to sustain the auxilia weight 12 in its elevated position, and ence the auxiliary weight 12 falls into enga ement with the weight 8, and adds its e ect thereto and causes the movable winding 3' to returnto its elevated or lowest voltage position.

While I' have described the principle of my invention and the best mode I have contemplated. for applying this principle, other modifications w1l1 occur to those skilled in the art and, I aim in the appended claims to cover all modifications which do not involve a departure from the spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States, is

1. The combination with a constant current regulating device comprising a movable member and means tending to move said movable member to its lowest voltage position, of means for augmenting the efi'ect of the first mentioned means when the regulatingrdevice ceases to sup ly its load.

2. he combination with rent regulatin device comprising a movable member, 0 means for moving said movable member to a low voltage position and means for relieving said'regulating device from the effect of the first mentioned means during the normal operation of said re latin device and applying the said mentioned means thereto when the regulating device ceases to supply itsload.

3. The combination w1th a constant current regulating device comprisin a movable member, of an auxiliary win ing inductively related to a winding of said regulatin device, a weight for moving said movab e member to a low voltage position, an

a constant currst' electric motor connected to said auxiliary winding for relieving said regulating device from the switch, said swltc'h being actuated by said weight to stop the motor when the weight is near the end of its travel under themfiuence of said motor.

4. The combination with a constant current regulating device. comprising a movable member and a weight partially counterbalancing said movable member, of an .aux- .iliary weight for 'augumenting the pull of the first mentioned Weight, and means for raising said auxiliary weight from the path of travel of said first mentioned weight during the normal operation of the regulating device and allowing the auxiliary weight to rest upon the first mentioned weight when ilzhedregulating device ceases to supply its 5. The combination with a constant current regulating device com rising a movable member, of a weight or moving said movable member to a low voltage position, an electric ,motor for relieving said regulating device from the pull of said weight, a switch for stopping said motor when acted on by said Wei ht, and a stop for said weight, both sai switch and said stop being near the end of the path of travel of said weight when said'auxiliary weight is acted on by said motor.

6. The combination with av constant current regulating device comprising a movable member, of an auxiliary winding inductively related to a Winding of said regulating device, a weight-for moving said movable member to a ow voltage position, an electric motor connected to said auxillary winding for relievin said regulating device from the pull of sai weight, a resistance in series between said motor and said auxiliary winding, and a switch for short circuiting said reslstance, said switch bein acted on by said weight near the end 0 its travel under the influence of said motor to open the short circuit and said resistance being of substantially sufiicient value to substantially prevent the motor rotating.

In witness whereof, I have hereunto set my hand this 31st day of October, 1917.

J HUGH D. sANBoR-N.

pull of said weight, and a 

